Sub-picosecond to Sub-nanosecond Vibrational Energy Transfer Dynamics in Pentaerythritol Tetranitrate

Experimental Data

All data are saved as a .csv file. Each transient .csv file is labeled according to molecule, file contents, polarization, pump laser power, spectrometer grating position, and a date (e.g. PETN_TA_para_1.8mW_11.1um_06Feb2020.csv). The first column contains frequencies (in cm-1) while the first row indexes each time delay (in ps). Transient spectra at select time delays are similarly labeled (e.g. PETN_spectra_7.8um_FTIRcorr_07Feb2020.csv) with the same data organization within each file. The select transient spectra shown at 1660 cm-1 were taken from the 6.1 µm "TA" dataset. The static PETN FTIR and 33°C ThDIR spectra are given as two column .csv files: the first column is frequency (in cm-1) while the second column is either transmission
or \(\Delta \mathrm{OD}\).

Theory Data

Included in the data repository are all of the necessary inputs to perform the vibrational analysis using the Phonopy software package. The minimized PETN crystal used in the nite displacement calculations is given as a POSCAR file format to be used in VASP, the enumeration of all displacements used in the first anharmonic expansion is given in disp_fc3.yaml. The collection of all individual VASP calculations into second- and third-order force constants are contained in the .hdf5 files. The remaining files contain all of the details for the Phonopy calculations performed, per-mode population adjustments in the JDOS are achieved by modifying the phono3py/phonon3/triplets.py source code file which is distributed with all versions of the code. Short movies of each IR mode  and all phonon modes between 0–800 cm-1 are presented in .gif format; filenames are either the calculated frequency or, in the case of several modes, the approximate center frequency.